Industrial sweepers are typically motor driven vehicles that employ a rotating broom to lift debris from a surface such as a floor. Such sweepers commonly rely upon a cylindrical broom, which rotates about an axis which is parallel to the floor surface, to lift debris that is then deposited in a hopper. The cylindrical broom is typically located beneath the sweeper body and is rotated so that the brushes of the broom move against the floor surface. Some sweepers also include an additional cylindrical broom or brooms which project outwardly from the sweeper and sweep debris into the path of the sweeper thereby broadening the sweeping path.
Such cylindrical brooms are normally mounted on a drive shaft for rotationally driving the broom. In this regard, the cylindrical broom is formed as a hollow cylindrical body with broom brushes mounted on the outer surface. The drive shaft is received within the cylindrical body and power is transmitted from the drive shaft to the broom by hubs mounted on the ends of the cylindrical body that interconnect to a mating spindle mounted to the shaft, thereby linking the shaft and broom.
In operation, the drive hubs are subject to considerable radial and torsional loads. These loads are due to, among other things, the substantial weight of the broom, downward pressure exerted on the broom for improved sweeping, and frictional forces incident to rotation of the broom against the floor surface, together with angular accelerations due to starts and stops of the broom.
In addition to bearing such loads, the drive hubs are disengaged from and then re-engaged to the drive shaft spindle during broom changing or replacement. In intense industrial use, the brooms need to be replaced periodically due to brush wear. The brooms may also be changed to address different sweeping conditions. For example, different brush materials and patterns may be desired depending on the type of debris and surface to be swept.
Therefore, the drive hubs must be strong enough to withstand the substantial radial and axial loads experienced in operation. Additionally, it is desirable for the drive hubs to be designed in conjunction with the spindles for simple broom changing or replacement. Moreover, the drive hubs should preferably be lightweight for improved efficiency and are preferably of simple construction and inexpensive to produce.
Currently, most if not all drive hubs are constructed as a plastic annulus which engages the broom body at an outer surface and engages the drive shaft spindle at an inner surface. The drive hub is keyed to the drive shaft spindle by way of two lugs which project inwardly from the inner surface of the drive hub into mating recesses of the spindle at diametrically opposed locations. The annular body normally includes an inner wall and an outer wall connected by spaced radial ribs.
In one conventional drive hub, a narrow rib extends outwardly from a center of each of the hollow lugs to the outer wall. Another conventional drive hub includes three ribs of equal axial depth spaced across the width of each of the hollow lugs. Yet another conventional drive hub includes a reinforcing mass, extending lengthwise from each of the solid lugs to the outer wall, having a circumferential width and axial depth approximately as great as those of the lug. The reinforcing mass is interrupted by four axially oriented cylindrical holes or cavities extending nearly through the depth of the mass.